A CIS (CMOS image sensor) according to the related art includes a photodiode area that receives a light signal to convert the light signal into an electric signal, and a transistor area that processes the electric signal.
The CIS according to the related art reproduces colors by obtaining green, blue, and red (G/B/R) color signals from four pixels having the same size.
However, outputs of the G/R/B color signals may vary depending on a junction profile of a photodiode, a wavelength of light, and a structure of the CIS. If a color pixel has a low-level output, more gain is needed to increase the output of the color signal, so that variable amplification must be performed for each color pixel. In this case, noise components are also amplified, so that image quality of the CIS may be degraded.